Stabilized styrene copolymers containing elastomer particles modified with a hindered amine

ABSTRACT

ABS copolymers and similar styrene or α-methylstyrene copolymers with contain an elastomer phase are stabilized against light-induced degradation by a) incorporation of a copolymerizable sterically hindered amine in, and b) addition of a non-copolymerizable sterically hindered amine to, the copolymer. Preferred sterically hindered amines are polyalkylpiperidines.

The present invention relates to light-stabilised copolymers of styreneor α-methylstyrene and at least one comonomer, which copolymers containcrosslinked elastomer particles.

Styrene copolymers which contain elastomer particles are thermoplasticswhich exhibit high impact strength. They are preferably graftcopolymers, consisting of a thermoplastic styrene copolymer matrix whichcontains crosslinked elastomer particles as disperse phase, thecopolymer grafted onto the elastomer particles acting as phase promoter.These styrene copolymers are prepared by subjecting slightly crosslinkedelastomer particles to graft polymerisation with styrene and one or morecomonomers. The slightly crosslinked elastomer particles can be preparedby mass phase inversion or by emulsion polymerisation. Examples ofsuitable elastomers are polybutadiene, butadiene/acrylonitrile orbutadiene/styrene copolymers, ethylene/propylene/diene terpolymers andacrylate elastomers, for example polybutyl acrylate and its copolymers.

Graft copolymers of styrene/acrylonitrile on polybutadiene are calledABS polymers, and graft copolymers of styrene/methyl methacrylate onpolybutadiene are called MBS polymers. In addition to these two mostimportant types, other styrene copolymers having elastomer phases havealso been disclosed, as well as their polymer blends with styrenecopolymers or other thermoplastics. In this connection, reference ismade to Encyclopedia Polymer Sci. Engng., J. Wiley 1985, Vol. 1, pages388-426; Ullmanns Encyclop. d. techn. Chemie (Ullmans Encyclopedia ofIndustrial Chemistry), Verlag Chemie 1980, Volume 19, pages 277-295.

Plastics of the ABS or MBS type are engineering plastics which are usedin bulk, for example for the production of household appliances,electrical appliances or sports equipment and of automotive parts. Foroutdoor use, these polymers must be stabilised to light and oxygen. Itis known that elastomer/styrene graft copolymers age rapidly and therebybecome brittle. For example, when ABS polymers were exposed to UV light,disappearance of the double bonds in the polybutadiene phase and at thesame time embrittlement of the polymer were observed, resultingultimately in the loss of impact strength (G. Scott and M. Tahan, Eur.Polym. J. 13 (1977)982).

For stabilisation, antioxidants and light stabilisers are added to thesepolymers. The light stabilisers used at present are mostly stericallyhindered amines, especially in conjunction with UV absorbers. Suchcombinations are recommended, for example, in DE-A-2 417 535, for alltypes of styrene copolymers. This constitutes stabilisation by theaddition of light stabilisers (physical mixture).

In EP-A-337 431 the proposal has been made to incorporate stericallyhindered amines into the elastomer phase by chemical means. This can bedone by graft copolymerisation of ethylenically unsaturated stericallyhindered amines onto the elastomer particles. Particularly suitablesterically hindered amines are unsaturated derivatives of2,2,6,6-tetramethylpiperidine, such as4-acryloyloxy-1,2,2,6,6-pentamethylpiperidine. Grafting is preferablycarried out in aqueous emulsion. Subsequently a mixture of styrene orα-methylstyrene and at least one comonomer is grafted onto the modifiedelastomer particles, whereby the light stabiliser is bonded permanentlyto the elastomer phase of the copolymer. This is important because theelastomer phase is sensitive to photooxidative degradation.

It is also disclosed in EP-A-337 431 that other known stabilisers can beadded to the copolymers stabilised in this manner, typicallyantioxidants, UV absorbers, metal deactivators or phosphites. No mentionis made in this publication of the physical addition of a furthersterically hindered amine, as it was not be expected that a secondsterically hindered amine would have an additional effect.

Surprisingly, however, it has been found that the intrinsically goodstabilisation imparted by the chemical incorporation of a stericallyhindered amine into the elastomer phase can be substantially enhanced byadding to the final copolymer a second sterically hindered amine whichis not unsaturated and therefore not chemically incorporated.

Accordingly, the invention relates to a light-stabilised copolymer ofstyrene or α-methylstyrene and at least one comonomer, which copolymercontains crosslinked elastomer particles which are modified bycopolymerisation with an unsaturated derivative of a sterically hinderedamine, and which copolymer additionally contains a sterically hinderedamine which is not unsaturated.

These copolymers are preferably graft copolymers of styrene and at leastone comonomer on the modified crosslinked elastomer.

The comonomer may be any polymerisable unsaturated compound, for examplean acrylic acid, methacrylic acid or maleic acid derivative or a styrenederivative. The comonomer is preferably acrylonitrile or methylmethacrylate. It is also possible to use two comonomers, for examplemixtures of arylonitrile and methyl methacrylate or mixtures ofacrylonitrile or methyl methacrylate with small amounts of vinylacetate, butyl acrylate or maleates.

The copolymers are preferably copolymers of styrene and acrylonitrile orstyrene and methyl methacrylate.

The elastomer may be any elastomer which is suitable for graftcopolymerisations. Typical examples of such elastomers arepolybutadiene, butadiene/acrylonitrile copolymers, butadiene/styrenecopolymers, ethylene/propylene/diene terpolymers or polybutyl acrylateand its copolymers. The preferred elastomer is polybutadiene. Thepreparation of these elastomer particles is carried out by knownprocesses, for example by mass polymerisation or suspensionpolymerisation, but preferably by emulsion polymerisation. The elastomerparticles are slightly crosslinked and normally have a mean diameter offrom 0.1 to 0.5 μm, preferably from 0.5 to 20 μm.

The elastomer is modified with the sterically hindered amine bycopolymerisation. The copolymerisation can be carried out during thepreparation of the elastomer or as graft copolymerisation onto thecrosslinked elastomer. Grafting with the sterically hindered amine canbe effected simultaneously with grafting with the styrene/comonomermixture. The process is preferably carried out in two steps by firstgrafting the unsaturated derivative of the sterically hindered amine andthen the styrene/comonomer mixture. The graft polymerisation ispreferably carried out in emulsion.

A copolymerisable unsaturated derivative of2,2,6,6-tetramethylpiperidine is preferably used as the unsaturatedderivative of a sterically hindered amine. The unsaturated group may bepresent in a substituent in the 4-position and/or 1-position of thepiperidine ring.

Unsaturated groups include preferably acryloyl and methacryloyl groups,as well as maleic acid groups, vinyl ether groups and allyl ethergroups, allylamino groups or crotonyl groups.

The copolymerisation with the elastomer is preferably carried out usinga compound of formula I ##STR1## wherein n is 1 or 2 and X is --O-- or--N(R₃)--, R₁ if n=1, is C₁ -C₁₈ alkyl, C₂ -C₂₀ alkenyl, C₅ -C₈cycloalkyl, C₇ -C₉ phenylalkyl, phenyl, phenyl which is substituted byhalogen, C₁ -C₄ alkyl or C₁ -C₄ alkoxy, or is a R₄ OOC--CH═CH-- groupand, if n=2, is C₂ -C₁₀ alkylene, vinylene, C₆ -C₁₂ arylene orcyclohexylene,

R₂ is hydrogen, O., C₁ -C₁₂ alkyl, C₃ -C₅ alkenyl, C₇ -C₉ phenylalkyl,C₁ -C₁₈ alkoxy, C₅ -C₈ cycloalkoxy, C₇ -C₉ phenylalkoxy, C₂ -C₁₀alkanoyl, C₃ -C₆ alkenoyl or a group of formula Ia ##STR2## R₃ ishydrogen, C₁ -C₁₂ alkyl or C₅ -C₈ cycloalkyl,

R₄ is hydrogen or C₁ -C₁₂ alkyl,

R₅ is hydrogen, CH₃ or CN, and

R₆ is hydrogen, C₁ -C₁₂ alkyl or phenyl,

with the proviso that at least one of the substituents R₁ and R₂contains an ethylenic double bond.

It is also preferred to use the compounds of formula II ##STR3## whereinR₂ is hydrogen, C₁ -C₁₂ alkyl, C₃ -C₅ alkenyl, C₇ -C₉ phenylalkyl, C₁-C₁₈ alkoxy, C₅ -C₈ cycloalkoxy, C₇ -C₉ phenylalkoxy or C₂ -C₁₀alkanoyl.

Preferred compounds of formula I are

a) those wherein n is 1, X is --O--, R₁ is C₂ -C₅ alkenyl and R₂ ishydrogen, C₁ -C₄ alkyl, allyl, benzyl or acetyl,

b) those wherein n is 1 or 2, X is --O--, R₁, if n=1, is C₁ -C₁₈ alkyl,cyclohexyl or phenyl and, if n=2, is C₂ -C₈ alkylene and R₂ is C₃ -C₆alkenoyl,

c) those wherein n is 1, X is --O--, R₁ is C₂ -C₅ alkenyl and R₂ is agroup of formula Ia, wherein R₅ and R₆ are hydrogen or CH₃.

In these formulae, R₁, R₂, R₃, R₄ and R₆ as alkyl may be unbranched orbranched and are typically methyl, ethyl, n-propyl, isopropyl, n-butyl,sec-butyl, tert-butyl, isopentyl, n-hexyl, n-octyl, 2-ethylhexyl,n-decyl, isoundecyl or n-dodecyl. R₁ as alkyl may also be tetradecyl,hexadecyl or octadecyl sein.

R₁ as C₂ -C₂₀ alkenyl may be vinyl, propenyl, isopropenyl, butenyl,pentenyl, undecenyl or oleyl sein, preferably vinyl and 2-propenyl(isopropenyl). R₂ as C₃ -C₅ alkenyl is preferably allyl.

R₁ and R₃ as C₅ -C₈ cycloalkyl may be cyclopentyl, cyclohexyl orcyclooctyl. Cyclohexyl is preferred.

R₁ and R₂ as C₇ -C₉ phenylalkyl may be benzyl, phenylethyl orphenylpropyl. Benzyl is preferred.

R₂ as C₁ -C₁₈ alkoxy may preferably be C₆ -C₁₀ alkoxy. R₂ as C₅ -C₈cycloalkoxy may preferably be cyclohexyloxy. R₂ as C₇ -C₉ phenylalkoxymay preferably be benzyloxy or phenylethoxy.

R₂ as C₂ -C₁₀ alkanoyl may be acetyl, propionyl, butyroyl, isobutyroyl,n-pentanoyl, tert-pentanoyl, hexanoyl, octanoyl or isodecanoyl. Acetylis preferred. R₂ as C₃ -C₆ alkenoyl is preferably acryloyl ormethacryloyl.

R₁ as C₂ -C₁₀ alkylene may be dimethylene, trimethylene, tetramethylene,hexamethylene, octamethylene, decamethylene, 2,2-dimethyltrimethylene or1,3,3-trimethyltetramethylene.

R₁ as C₆ -C₁₂ arylene may be phenylene, naphthylene or diphenylene,preferably phenylene.

All compounds of formulae I and II contain at least one ethylenic doublebond which enables the compound to be copolymerised. The compounds may,however, also contain two double bonds. Such compounds are preferablycopolymerised during the preparation of the elastomer.

Illustrative examples of compounds of formula I are:

1,2,2,6,6-pentamethyl-4-piperidinyl acrylate, methacrylate or crotonate,

2,2,6,6-tetramethyl-4-piperidinyl acrylate, methacrylate or crotonate,

1-benzyl-2,2,6,6-tetramethyl-4-piperidinyl acrylate, methacrylate orcrotonate,

1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl acrylate, methacrylate orcrotonate,

N-(2,2,6,6-tetramethyl-4-piperidinyl)acrylamide,

N-methyl-N-(1,2,2,6,6-pentamethyl-4-piperidinyl)methacrylamide

N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidinyl)acrylamide,

monoethyl mono(1,2,2,6,6-pentamethyl-4-piperidinyl)maleinate

bis(2,2,6,6-tetramethyl-4-piperidinyl)fumarate,

monohexylmaleate-N-(2,2,6,6-tetramethyl-4-piperidinyl)-N-butylamide,

N,N'-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-N,N'-dibutylmaleamide,

1-acryloyl-2,2,6,6-tetramethyl-4-acetoxypiperidine,

1-methacryloyl-2,2,6,6-tetramethyl-4-butyroyloxypiperidine,

1-crotonyl-2,2,6,6-tetramethyl-4-benzoyloxypiperidine,

1-acryloyl-2,2,6,6-tetramethyl-4-acryloyloxypiperidine,

1-methacryloyl-2,2,6,6-tetramethyl-4-methacryloyloxypiperidine,

1-acryloyl-2,2,6,6-tetramethyl-4-(4-chlorobenzoyloxy) piperidine,

bis(1-acryloyl-2,2,6,6-tetramethyl-4-piperidinyl) sebacate,

bis(1-methacryloyl-2,2,6,6-tetramethyl-4-piperidinyl) adipate,

bis(1-acryloyl-2,2,6,6-tetramethyl-4-piperidinyl) succinate,

bis(1-crotonoyl-2,2,6,6-tetramethyl-4-piperidinyl) phthalate,

N-(1-acryloyl-2,2,6,6-tetramethyl-4-piperidinyl) acetamide,

N-(1-acryloyl-2,2,6,6-tetramethyl-4-piperidinyl)-N-butylbenzamide,

N,N'-bis(1-methacryloyl-2,2,6,6-tetramethyl-4-piperidinyl)-N,N'-dicyclohexylisophthalamide,

1-(2-acryloyloxyethyl)-4-acryloyloxy-2,2,6,6-tetramethylpiperidine,

1-(2-methacryloyloxyethyl)-4-methacryloyloxy-2,2,6,6-tetramethylpiperidine,

1-(2-acryloyloxypropyl)-4-acryloyloxy-2,2,6,6-tetramethylpiperidine.

Illustrative examples of compounds of formula II are:

N-(2,2,6,6-tetramethyl-4-piperidinyl) maleimide,

N-(1,2,2,6,6-pentamethyl-4-piperidinyl) maleimide,

N-(1-benzyl-2,2,6,6-tetramethyl-4-piperidinyl) maleimide,

N-(1-acetyl-2,2,6,6-tetramethyl-4-piperidinyl) maleimide.

However, the eligible unsaturated derivatives of sterically hinderedamines are by no means restricted to compounds of formulae I and II. Inprinciple, it is possible to use any unsaturated derivative of asterically hindered amine, provided it is capable of undergoingcopolymerization with the elastomer component.

The unsaturated sterically hindered amine can be copolymerised alone ortogether with other unsaturated compounds. Such copolymers are typicallyalkyl acrylates, alkyl methacrylates, acrylamides and methacrylamides,acrylonitrile or methacrylonitrile, preferably alkyl(meth)acrylates.

The mixture of styrene or α-methylstyrene and the comonomer can begrafted together with the unsaturated derivative of a stericallyhindered amine onto the elastomer particles. The graft copolymerisationis preferably carried out in two steps. In the first step, theunsaturated sterically hindered amine is grafted, alone or together withother unsaturated compounds, onto the elastomer. In a second step, themixture of styrene or α-methylstyrene and the comonomer is then graftedonto the elastomer.

Alternatively, the elastomer particles grafted with the unsaturatedsterically hindered amine can be mixed with a separately preparedstyrene or α-methylstyrene copolymer in a second step. However, it ispreferred to graft the styrene phase onto the modified elastomer.

The copolymerisation or graft copolymerisation is carried out byconventional methods. It is preferably carried out in emulsion. Theemulsifier used is preferably an anionic surfactant, for example analkali metal sulfonate or alkali metal resinate. The particle size ofthe polymer can be controlled by adjusting the amount and metering thesurfactant. Water-soluble free radical initiators, for example potassiumpersulfate, are preferably used as polymerisation initiators for thepreparation of the elastomer phase. For the polymerisation of thestyrene phase, it is preferred to use redox initiators, for example thesystem iron(II)salt/organic peroxide. Both stages of the polymerisationare preferably carried out at below 100° C., in particular at 40°-70° C.The copolymer may be isolated by coagulation or by spray drying.Coagulation of the emulsion can be achieved by adding water-solublesalts, by increasing the temperature, by reducing the pH or by freezing.

The addition of the sterically hindered amine which is not unsaturatedcan be made before or after the coagulation. The addition is preferablymade to the isolated and dried copolymer. All methods commonly used forplastics additives are suitable for this addition, such as blending inpowder form, or incorporation on a mixer roll or in an extruder.

The amount of sterically hindered amine incorporated by copolymerisationis preferably 0.1 to 10% by weight of the copolymer, and the amount ofthe sterically hindered amine which is not unsaturated is 0.05 to 5% byweight of the copolymer.

The sterically hindered amine which is not unsaturated is preferably apolyalkylpiperidine which contains at least one group of formula III##STR4## wherein R is hydrogen or methyl. Preferably R is hydrogen. Suchcompounds are derivatives of 2,2,6,6-tetramethylpiperidine. Thesecompounds can be low molecular (MW<700) or high molecular (oligomer,polymer). They preferably carry in 4-position one or two polarsubstituents or a polar spiro ring system.

Particularly important light stabilisers are the following classes ofpolyalkylpiperidines.

a) Compounds of formula IV ##STR5## wherein n is an integer from 1 to 4,preferably 1 or 2, R is hydrogen or methyl, R₁₁ is hydrogen, oxyl,hydroxyl, C₁ -C₁₂ alkyl, C₇ -C₁₂ aralkyl, C₁ -C₁₈ alkoxy, C₅ -C₈cycloalkoxy, C₇ -C₉ phenylalkoxy, C₁ -C₈ alkanoyl, C₁ -C₁₈ alkanoyloxy,benzoyloxy, glycidyl or a --CH₂ CH(OH)--Z group, wherein Z is hydrogen,methyl or phenyl, the preferred meanings of R₁₁ being H, C₁ -C₄ alkyl,benzyl, acetyl, C₁ -C₁₂ alkoxy, C₇ -C₉ phenylalkoxy or cyclohexyloxy andR₁₂, if n is 1, is hydrogen, C₁ -C₁₈ alkyl which may be interrupted byone or more oxygen atoms, cyanoethyl, benzyl, glycidyl, a divalentradical of a saturated aliphatic, cycloaliphatic, araliphatic oraromatic carboxylic acid, carbamic acid or phosphorus-containing acid,or a monovalent silyl radical, preferably a radical of a saturatedaliphatic carboxylic acid of 2 to 18 carbon atoms, of a saturatedcycloaliphatic carboxylic acid of 7 to 15 carbon atoms, or of anaromatic carboxylic acid of 7 to 15 carbon atoms, and, if n is 2, is C₁-C₁₂ alkylene, xylylene, a divalent radical of a saturated aliphatic,cycloaliphatic, araliphatic or aromatic dicarboxylic acid, dicarbamicacid or phosphorus-containing acid, or a divalent sylyl radical,preferably the divalent radical of a saturated aliphatic dicarboxylicacid of 2 to 12 carbon atoms, of a saturated cycloaliphatic or aromaticdicarboxylic acid of 8 to 14 carbon atoms, or of a saturated aliphatic,cycloaliphatic or aromatic dicarbamic acid of 8 to 14 carbon atoms, if nis 3, is a trivalent radical of a saturated aliphatic tricarboxylic acidof 6 to 12 carbon atoms or of an aromatic tricarboxylic acid of 9 to 15carbon atoms, and, if n is 4, is the tetravalent radical of a saturatedaliphatic tetracarboxylic acid of 8 to 12 carbon atoms or of an aromatictetracarboxylic acid of 10 to 16 carbon atoms.

Substituents defined as C₁ -C₁₂ alkyl may be methyl, ethyl, n-propyl,n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl,n-decyl, n-undecyl or n-dodecyl.

R₁₁ or R₁₂ as C₁ -C₁₈ alkyl may be the groups listed above and, inaddition, may be n-tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl.

R₁₁ as C₇ -C₁₂ aralkyl is preferably phenethyl and, most preferably,benzyl.

R₁₁ as C₁ -C₈ alkanoyl is typically formyl, propionyl, butyryl, octanoyland, preferably, acetyl.

R₁₂ as a monovalent radical of a carboxylic acid is typically a radicalof acetic acid, caproic acid, stearic acid, acrylic acid, methacrylicacid, benzoic acid, or a β-(3,5-di-tert.-butyl-4-hydroxyphenyl)propionicacid radical.

R₁₂ as a divalent radival of a dicarboxylic acid may be a radical ofmalonic acid, succinic acid, glutaric acid, adipic acid, suberic acid,sebacic acid, phthalic acid, dibutylmalonic acid, dibenzylmalonic acidor butyl-(3,5-di-tert-butyl-4-hydroxybenzyl)malonic acid.

R₁₂ as a trivalent radical of a tricarboxylic acid may be a radical oftrimellitic acid, citric acid or nitrilotriacetic acid.

R₁₂ as a tetravalent radical of a tetracarboxylic acid may be atetravalent radical of butane-1,2,3,4-tetracarboxylic acid or ofpyromellitic acid.

R₁₂ as a divalent radical of a dicarbamic acid may be a radical ofhexamethylenedicarbamic acid or a radical of 2,4-toluylenedicarbamicacid. Compounds of formula IV are preferred wherein R is hydrogen, R₁₁is hydrogen or methyl, n is 2 and R₁₂ is the diacyl radical of analiphatic dicarboxylic acid of 4 to 12 carbon atoms.

The following compounds exemplify polyalkylpiperidine compounds of thisclass:

1) 4-hydroxy-2,2,6,6-tetramethylpiperidine

2) 1-benzyl-4-hydroxy-2,2,6,6-tetramethylpiperidine

3) 1-(4-tert-butyl-2-butenyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine

4) 4-stearoyloxy-2,2,6,6-tetramethylpiperidine

5) 1-ethyl-4-salicyloyloxy-2,2,6,6-tetramethylpiperidine

6)1,2,2,6,6-pentamethylpiperidin-4-yl-β-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate

7) bis(1-benzyl-2,2,6,6-tetramethylpiperidin-4-yl) maleate

8) bis(2,2,6,6-tetramethylpiperidin-4-yl) succinate

9) bis(2,2,6,6-tetramethylpiperidin-4-yl) glutarate

10) bis(2,2,6,6-tetramethylpiperidin-4-yl) adipate

11) bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate

12) bis(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate

13) bis(1,2,3,6-tetramethyl-2,6-diethylpiperidin-4-yl) sebacate

14)tetra(2,2,6,6-tetramethylpiperidin-4-yl)-butane-1,2,3,4-tetracarboxylate

15)tetra(1,2,2,6,6-pentamethylpiperidin-4-yl)-butane-1,2,3,4-tetracarboxylate

16) tris(2,2,6,6-tetramethylpiperidin-4-yl) trimellitate,

17) bis(2,2,6,6-tetramethylpiperidin-4-yl) diethylmalonate

18) bis(1,2,2,6,6-pentamethylpiperidin-4-yl) dibutylmalonate

19) bis(1,2,2,6,6-pentamethylpiperidin-4-yl)butyl-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate

20) bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate

21) bis(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate

22)hexane-1',6'-bis(4-carbamoyloxy-1-n-butyl-2,2,6,6-tetramethylpiperidine)

23)toluene-2',4'-bis(4-carbamoyloxy-1-n-propyl-2,2,6,6-tetramethylpiperidine)

24) dimethyl bis(2,2,6,6-tetramethylpiperidin-4-oxy)silane

25) phenyl tris(2,2,6,6-tetramethylpiperidin-4-oxy)silane

26) tris(1-propyl-2,2,6,6-tetramethylpiperidin-4-yl)phosphite

27) tris(1-propyl-2,2,6,6-tetramethylpiperidin-4-yl)phosphate

28) phenyl [bis(1,2,2,6,6-pentamethylpiperidin-4-yl)] phosphonate

29) 4-hydroxy-1,2,2,6,6pentamethylpiperidine

30) 4-hydroxy-N-hydroxyethyl-2,2,6,6-tetramethylpiperidine

31) 4-hydroxy-N-(2-hydroxypropyl)-2,2,6,6-tetramethylpiperidine

32) 1-glycidyl-4-hydroxypropyl)-2,2,6,6-tetramethylpiperidine;

b) compounds of formula V ##STR6## wherein n is 1 or 2, R and R₁₁ are asdefined in a), R₁₃ is hydrogen, C₁ -C₁₂ alkyl, C₂ -C₅ hydroxyalkyl, C₅-C₇ cycloalkyl, C₇ -C₈ aralkyl, C₂ -C₁₈ alkanoyl, benzoyl or a group offormula ##STR7## and R₁₄, if n is 1, is hydrogen, C₁ -C₁₈ alkyl, C₅ -C₇cycloalkyl, C₁ -C₄ alkyl which is substituted by a hydroxy, cyano,alkoxycarbonyl or carbamide group, glycidyl, a group of formula --CH₂--CH(OH)--Z or --CONH--Z, wherein Z is hydrogen, methyl or phenyl; and,if n is 2, is C₂ -C₁₂ alkylene, C₆ -C₁₂ arylene, xylylene, a --CH₂--CH(OH)--CH₂ -- group or a --CH₂ --CH(OH)--CH₂ --O--D--O-- group,wherein D is C₂ -C₁₀ alkylene, C₆ -C₁₅ arylene, C₆ -C₁₂ cycloalkyleneor, with the proviso that R₁₃ is not alkanoyl or benzoyl, R₁₄ may alsobe a divalent radical of a saturated aliphatic, cycloaliphatic oraromatic dicarboxylic acid or dicarbamic acid or also the --CO-- group,or R₁₃ and R₁₄, when taken together, if n is 1, may be the divalentradical of a saturated aliphatic, cycloaliphatic or aromatic 1,2- or1,3-dicarboxylic acid.

Substituents defined as C₁ -C₁₂ alkyl or c₁ -C₁₈ alkyl are as previouslydefined in a) above.

Substituents defined as C₅ -C₇ cycloalkyl are preferably cyclohexyl.

R₁₃ as C₇ -C₈ aralkyl is preferably phenylethyl or, most preferably,benzyl. R₁₃ as C₂ -C₅ hydroxyalkyl is preferably 2-hydroxyethyl or2-hydroxypropyl.

R₁₃ as C₂ -C₁₈ alkanoyl may be propionyl, butyryl, octanoyl, dodecanoyl,hexadecanoyl, octadecanoyl, but is preferably acetyl.

R₁₄ as C₁ -C₄ alkyl which is substituted by a hydroxy, cyano,alkoxycarbonyl or carbamide group may be 2-hydroxyethyl,2-hydroxypropyl, 2-cyanoethyl, methoxycarbonylmethyl,2-ethoxycarbonylethyl, 2-aminocarbonylpropyl or2-(dimethylaminocarbonyl)ethyl.

Substituents defined as C₂ -C₁₂ alkylene may be ethylene, propylen,2,2-dimethylpropylene, tetramethylene, hexamethylene, octamethylene,decamethylene or dodecamethylene.

Substituents defined as C₆ -C₁₅ arylene may be o-, m- or p-phenylene,1,4-naphthylene or 4,4'-diphenylene.

D as C₆ -C₁₂ cycloalkylene is preferably cyclohexylene.

Preferred compounds of formula V are those wherein n is 1 or 2, R ishydrogen, R₁₁ is hydrogen or methyl, R₁₃ is hydrogen, C₁ -C₁₂ alkyl or agroup of formula ##STR8## and R₁₄, if n=1, is hydrogen or C₁ -C₁₂ alkyland, if n=2, is C₂ -C₈ alkylene.

The following compounds are illustrative examples of polyalkylpiperidinecompounds of this class:

33) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylene-1,6-diamine

34)N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylene-1,6-diacetamide

35) bis(2,2,6,6-tetramethylpiperidin-4-yl)amine

36) 4-benzoylamino-2,2,6,6-tetramethylpiperidine

37) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)-N,N'-dibutyladipamide

38)N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)-N,N'-dicyclohexyl-2-hydroxypropylen-1,3-diamine

39) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)-p-xylylenediamine

40) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)succinamide

41) dodecyl N-(2,2,6,6-tetramethylpiperidin-4-yl)-β-aminopropionate

42) the compound of formula ##STR9## 43)4-(bis-2-hydroxyethylamino)-1,2,2,6,6-pentamethylpiperidine 44)N-(2,2,6,6-tetramethylpiperidin-4-yl) -α-dodecylsuccinimide

c) compounds of formula VI ##STR10## wherein n is 1 or 2, R and R₁₁ areas defined in a) and R₁₅, if n is 1, is C₂ -C₈ alkylene or C₂ -C₈hydroxyalkylene or C₄ -C₂₂ acyloxyalkylene, and, if n is 2, is the(--CH₂)₂ C(CH₂ --)₂ group.

R₁₅ as C₂ -C₈ alkylene or C₂ -C₈ hydroxyalkylene may be ethylene,1-methylethylene, propylene, 2-ethylpropylene or2-ethyl-2-hydroxymethylpropylene.

R₁₅ as C₄ -C₂₂ acyloxyalkylene is 2-ethyl-2-acetoxymethylpropylene.

The following compounds are illustrative examples of polyalkylpiperidinecompounds of this class:

45) 9-aza-8,8,10,10-tetramethyl-1,5-dioxaspiro[5.5]undecane

46) 9-aza-8,8,10,10-tetramethyl-3-ethyl-1,5-dioxaspiro[5.5]undecane

47) 8-aza-2,7,7,8,9,9-hexamethyl-1,4-dioxaspiro[4.5]decane

48)9-aza-3-hydroxymethyl-3-ethyl-8,8,9,10,10-pentamethyl-1,5-dioxaspiro[5.5]undecane

49)9-aza-3-ethyl-3-acetoxymethyl-9-acetyl-8,8,10,10-tetramethyl-1,5-dioxaspiro[5.5]undecane

50)2,2,6,6-tetramethylpiperidine-4-spiro-2'-(1',3'-dioxane)-5'-spiro-5"(1",3"-dioxane)-2"-spiro-4'"-(2'",2'",6'",6'"-tetramethylpiperidine).

d) compounds of formulae VIIA, VIIB and VIIC ##STR11## wherein n is 1 or2, R and R₁₁ are as defined in a), R₁₆ is hydrogen, C₁ -C₁₂ alkyl,allyl, benzyl, glycidyl or C₂ -C₆ alkoxyalkyl and R₁₇, if n is 1, ishydrogen, C₁ -C₁₂ alkyl, C₇ -C₉ aralkyl, C₅ -C₇ cycloalkyl, C₂ -C₄hydroxyalkyl, C₂ -C₆ alkoxyalkyl, C₆ -C₁₀ aryl, glycidyl or a group offormula --(CH₂)_(p) --COO--Q or --(CH₂)_(p) --O--CO--Q, wherein p is 1or 2 and Q is C₁ -C₄ alkyl or phenyl, and, if n is 2, is C₂ -C₁₂alkylene, C₆ -C₁₂ arylene, a group --CH₂ --CH(OH)--CH₂ --O--D--O--CH₂--CH(OH)--CH₂ --, wherein D is C₂ -C₁₀ alkylene, C₆ -C₁₅ arylene or C₆-C₁₂ cycloalkylene, or a group --CH₂ CH(OZ')CH₂ --(OCH₂ --CH(OZ')CH₂)₂--, wherein Z' is hydrogen, C₁ -C₁₈ alkyl, benzyl, C₂ -C₁₂ alkanoyl orbenzoyl, T₁ and T₂ are each independently of the other C₁ -C₁₈ alkyl orC₆ -C₁₀ aryl or C₇ -C₉ aralkyl which are each unsubstituted orsubstituted by halogen or C₁ -C₄ alkyl, or T₁ and T₂, together with thelinking carbon atom, form a C₅ -C₁₂ cycloalkane ring.

Substituents defined as C₁ -C₁₂ alkyl may be methyl, ethyl, n-propyl,n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl,n-decyl, n-undecyl or n-dodecyl.

Substituents defined as C₁ -C₁₈ alkyl may be the groups named above and,in addition, n-tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl.

Substituents defined as C₂ -C₆ alkoxyalkyl may be methoxymethyl,ethoxymethyl, propoxymethyl, tert-butoxymethyl, ethoxyethyl,ethoxypropyl, n-butoxyethyl, tert-butoxyethyl, isopropoxyethyl orpropoxypropyl.

R₁₇, T₁ and T₂ as C₇ -C₉ aralkyl are preferably phenethyl or, mostpreferably, benzyl. A cycloalkane ring formed by T₁ and T₂ together withthe linking carbon atom may be a cyclopentane, cyclohexane, cyclooctaneor cyclododecane ring.

R₁₇ as C₂ -C₄ hydroxyalkyl may be 2-hydroxyethyl, 2-hydroxypropyl,2-hydroxybutyl or 4-hydroxybutyl.

R₁₇, T₁ and T₂ as C₆ -C₁₀ aryl are preferably phenyl, α- or β-naphthyl,which are each unsubstituted or substituted by halogen or C₁ -C₄ alkyl.

R₁₇ as C₂ -C₁₂ alkylene may be ethylene, propylene,2,2-dimethylpropylene, tetramethylene, hexamethylene, octamethylene,decamethylene or dodecamethylene.

R₁₇ as C₆ -C₁₂ arylene may be o-, m- or p-phenylene, 1,4-naphthylene or4,4'-diphenylene.

Z' as C₂ -C₁₂ alkanoyl may be propionyl, butyryl, octanoyl, dodecanoyl,but is preferably acetyl.

D as C₂ -C₁₀ alkylene, C₆ -C₁₅ arylene or C₆ -C₁₂ cycloalkylene is asdefined in b).

The following compounds are illustrative of polyalkylpiperidinecompounds of this class:

51) 3-benzyl-1,3,8-triaza-7,7,9,9-tetramethylspiro[4.5]decane-2,4-dione

52) 3-n-octyl-1,3,8-triaza-7,7,9,9-tetramethylspiro[4.5]decane-2,4-dione

53)3-glycidyl-1,3,8-triaza-7,7,8,9,9-pentamethylspiro[4.5]decane-2,4-dione

54) 1,3,7,7,8,9,9-heptamethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione

55)2-isopropyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4.5]decane

56)2,2-dibutyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro-[4.5]decane

57)2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxo-dispiro[5.1.11.2]heneicosane

58) 2-butyl-7,7,9,9-tetramethyl-1-oxa-4,8-diaza-3-oxo-spiro-[4,5]decane

59)8-acetyl-3-dodecyl-1,3,8-triaza-7,7,9,9-tetramethylspiro[4,5]-decane-2,4-dione

or the compounds of the following formulae: ##STR12##

e) compounds of formula VIII ##STR13## wherein n is 1 or 2 and R₁₈ is agroup of formula ##STR14## wherein R and R₁₁ is as defined in a), E is--O-- or --NR₂₁ --, A is C₂ -C₆ alkylene or --(CH₂)₃ --O-- and x is O or1, R₁₉ has the same meaning as R₁₈ or is a group selected from --NR₂₁R₂₂, --OR₂₃, --NHCH₂ OR₂₃ and --N(CH₂ OR₂₃)₂, R₂₀, if n=1, has the samemeaning as R₁₈ or R₁₉, and, if n=2, is a group --E--B--E--, wherein B isC₂ -C₆ alkylene which may be interrupted by --N(R₂₁)--, R₂₁ is C₁ -C₁₂alkyl, cyclohexyl, benzyl or C₁ -C₄ hydroxyalkyl or is a group offormula ##STR15##

R₂₂ is C₁ -C₁₂ alkyl, cyclohexyl, benzyl, C₁ -C₄ hydroxyalkyl, and R₂₃is hydrogen, C₁ -C₁₂ alkyl or phenyl, or R₂₁ and R₂₂, when takentogether, are C₄ -C₅ alkylene or C₄ -C₅ oxaalkylene, for example##STR16## or a group of formula ##STR17## or R₂₁ and R₂₂ are also each agroup of formula ##STR18##

Substituents defined as C₁ -C₁₂ alkyl may be methyl, ethyl, n-propyl,n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl,n-decyl, n-undecyl or n-dodecyl.

Substituents defined as C₁ -C₄ -hydroxyalkyl may be 2-hydroxyethyl,2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl or 4-hydroxybutyl.

A as C₂ -C₆ alkylene may be ethylene, propylene, 2,2-dimethylpropylene,tetramethylene or hexamethylene.

R₂₁ and R₂₂ together as C₄ -C₅ alkylene or oxaalkylene may betetramethylene, pentamethylene or 3-oxapentamethylene.

The following compounds are illustrative of polyalkylpiperidinecompounds of this class: ##STR19##

f) Oligomeric or polymeric compounds whose structural repeating unitcontains a 2,2,6,6-tetraalkylpiperidine radical of formula III,preferably polyesters, polyethers, polyamides, polyamines,polyurethanes, polyureas, polyaminotriazines, poly(meth)acrylates,poly(meth)acrylamides and the copolymers thereof which contain suchradicals.

Exemplary of 2,2,6,6-polyalkylpiperidine light stabilisers of this classare the compounds of the following formulae, wherein m is an integerfrom 2 to c. 200: ##STR20##

Of these classes of compounds, classes a), e) and f) are particularlysuitable, preferably compounds 8, 11, 12, 15, 19, 20, 69, 71, 75, 78, 86and 87.

Other known stabilisers may be added to the stabilised copolymers.Typical examples of such stabilisers are those of the following classes:

1. Antioxidants

1.1. Alkylated monophenols, for example2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, 2,6-di-nonyl-4-methylphenol.

1.2. Alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol.

1.3. Hydroxylated thiodiphenyl ethers, for example2,2'-thiobis(6-tert-butyl-4-methylphenol),4,4'-thiobis(6-tert-butyl-2-methylphenol).

1.4. Alkylidenebisphenols, for example2,2'-methylenebis(6-tert-butyl-4-methylphenol),2,2'-methylenebis(6-tert-butyl-4-ethylphenol),2,2'-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol],2,2'-methylenebis(4-methyl-6-cyclohexylphenol),2,2'-methylenebis(6-nonyl-4-methylphenol),2,2'-methylenebis(4,6-di-tert-butylphenol),2,2'-ethylidenebis(4,6-di-tert-butylphenol),2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol),2,2'-methylenebis[6-(α-methylbenzyl)-4-nonylphenol],2,2'-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4'-methylenebis(2,6-di-tert-butylphenol),4,4'-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis[3,3-bis(3'-tert-butyl-4'-hydroxyphenyl)butyrate],bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene,bis[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4methylphenyl]terephthalate.

1.5. Benzyl compounds, for example1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, isooctyl3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) dithiolterephthalate,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate,dioctadecyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, calcium saltof monoethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate,1,3,5-tris-(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.

1.6. Acylaminophenols, for example 4-hydroxylauranilide,4-hydroxystearanilide,2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-s-triazine,octyl N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

1.7. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, diethylene glycol,octadecanol, triethylene glycol, 1,6-hexanediol, pentaerythritol,neopentyl glycol, tris(hydroxyethyl) isocyanurate, thiodiethyleneglycol, N,N'-bis(hydroxyethyl)oxalyl diamide.

1.8. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acidwith mono- or polyhydric alcohols, e.g. with methanol, diethyleneglycol, octadecanol, triethylene glycol, 1,6-hexanediol,pentaerythritol, neopentyl glycol, tris(hydroxyethyl) isocyanurate,thiodiethylene glycol, N,N'-bis(hydroxyethyl)oxalyl diamide.

1.9. Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid withmono- or polyhydric alcohols, e.g. with methanol, diethylene glycol,octadecanol, triethylene glycol, 1,6-hexanediol, pentaerythritol,neopentyl glycol, tris(hydroxyethyl) isocyanurate, thiodiethyleneglycol, N,N'-bis(hydroxyethyl)oxalyl diamide.

1.10. Amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid e.g.N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylene-diamine,N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylene-diamine,N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.

2. UV absorbers and light stabilisers

2.1. 2-(2'-Hydroxyphenyl)benzotriazoles, for example the 5'-methyl,3',5'-di-tert-butyl, 5'-tert-butyl,5'-(1,1,3,3-tetramethylbutyl),5-chloro-3',5'-di-tert-butyl,5-chloro-3'-tert-butyl-5'-methyl,3'-sec-butyl-5'-tert-butyl,4'-octoxy,3',5'-di-tert-amyland 3',5'-bis(α,α-dimethylbenzyl) derivative.

2.2. 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy,4-octoxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy and2'-hydroxy-4,4'-dimethoxy derivative.

2.3. Esters of substituted and unsubstituted benzoic acids, for example,4-tert-butylphenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoylresorcinol, bis(4-tert-butylbenzoyl)-resorcinol,benzoylresorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxy-benzoate and hexadecyl3,5-di-tert-butyl-4-hydroxybenzoate.

2.4. Acrylates, for example ethyl α-cyano-β,β-diphenylacrylate, isooctylα-cyano-β,β-diphenylacrylate, methyl α-carbomethoxycinnamate, methylα-cyano-β-methyl-p-methoxy-cinnamate, butylα-cyano-β-methyl-p-methoxy-cinnamate, methylα-carbomethoxy-p-methoxycinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

2.5. Nickel compounds, for example nickel complexes of2,2'-thio-bis[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or1:2 complex, with or without additional ligands such as n-butylamine,triethanolamine or N-cyclohexyldiethanolamine, nickeldibutyldithiocarbamate, nickel salts of4-hydroxy-3,5-di-tert-butylbenzyl-phosphonic acid monoalkyl esters, e.g.of the methyl or ethyl ester, nickel complexes of ketoximes, e.g. of2-hydroxy-4-methyl-phenyl undecyl ketoneoxime, nickel complexes of1-phenyl-4-lauroyl-5-hydroxypyrazole, with or without additionalligands.

2.6. Oxalyl diamides, for example 4,4'-dioctyloxyoxanilide,2,2'-dioctyloxy-5,5'-di-tert-butoxanilide,2,2'-didodecyloxy-5,5'-di-tert-butoxanilide, 2-ethoxy-2'-ethyloxanilide,N,N'-bis(3-dimethylaminopropyl)oxalamide,2-ethoxy-5-tert-butyl-2'-ethyloxanilide and its mixture with2-ethoxy-2'-ethyl-5,4'-di-tert-butoxanilide and mixtures of ortho- andpara-methoxy-disubstituted oxanilides and mixtures of o- andp-ethoxydisubstituted oxanilides.

2.7.2-(2-Hydroxyphenyl)-1,3,5-triazines, for example2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxy-phenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxy-phenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.

3. Metal deactivators, for example N,N'-diphenyloxalyl diamide,N-salicylal-N'-salicyloylhydrazine, N,N'-bis(salicyloyl)hydrazine,N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine,3-salicyloyl-amino-1,2,4-triazole, bis(benzylidene)oxalic dihydrazide.

4. Phosphites and phosphonites, for example triphenyl phosphite,diphenylalkyl phosphites, phenyldialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite,diisodecyl pentaerythritol diphosphite, bis(2,4-di-tertbutylphenyl)pentaerythritol diphosphite, tristearyl sorbitol triphosphite,tetrakis-(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite,3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.

The concurrent use of phenolic antioxidants, UV absorbers and ofphosphites or phosphonites is especially important. These additives arepreferably incorporated in an amount of 0.05 to 5% by weight, based onthe copolymer.

Further conventional modifiers used in plastics technology may also beadded, typically pigments, fillers, reinforcing agents, lubricants,flame retardants, antistatic agents or blowing agents.

The invention is illustrated by the following non-limitative Examples inwhich, unless otherwise stated, parts and percentages are by weight.

EXAMPLE 1

1150 g of a polybutadiene latex with 59% solids content BAYGAL® 2004KBayer AG) and 1220 g of deionised water are charged to a 3 literreactor, degassed 4 times, stirred under argon at 100 rpm and heatedover 30 minutes to 60° C. Then 0.1 g of tert-dodecylmercaptan and 54 gof 4-acryloyloxy-1,2,2,6,6-pentamethylpiperidine (APP) are added. Thestirring rate is increased for 2 minutes to c. 250 rpm, then reduced to100 rpm and 2 g potassium persulfate are added immediately. Afterpolymerisation for 7 hours the latex is cooled to room temperature.

In a 3 liter stirred vessel, 680 g of this latex are diluted with 600 gof water. After degassing 4 times, the temperature is brought to 60° C.over half an hour. An aqueous solution of emulsifier is then added. Itconsists of 31 ml of a 10% solution of potassium rosinate (DRESINATE®731, Hercules Inc.), 2.7 ml of a 10% NaOH solution, 6.7 ml of a 10%glucose solution and 1.6 ml of a 10% solution of sodiumalkylnaphthalenesulfonate (TAMOL® NN, BASF AG). The initiator isprepared by dissolving 500 mg of FeSO₄.7H₂ O in 50 ml of water, adding16 ml of this solution to 36 ml of water and to 4.8 g of Na₄ P₂ O₇ in 48ml of water. After stirring for 15 minutes, this 100 ml degassedsolution is added to the latex. Then 400 g of styrene, 200 gacrylonitrile, 4.0 g of tert-dodecylmercaptan and 4.0 g of cumenehydroperoxide are added and the mixture is stirred for 7 hours at 60° C.at a stirring rate of 100 rpm. All these operations are carried out inthe absence of oxygen.

To the latex are added 10 ml of a 20% aqueous emulsion of a phenolicantioxidant (IGANOX® 1076, Ciba-Geigy AG) and 100 ml of a 10% solutionof the sodium salt of ethylenediaminetetraacetic acid, and the latex isfiltered over glass wool.

With stirring (300 rpm), the emulsion is added rapidly to 4 liters ofwater of 90° C. and 70 ml of an aqueous solution of 10% MgSO₄.7H₂ O and5% acetic acid and precipitated. The liquid phase above the precipitatedcopolymer has a pH of 5.3, which is adjusted to 8 by adding sodiumcarbonate solution. The coagulation is brought to completion by stirringfor 30 minutes at 90° C. The copolymer, which has precipitated in powderform, is isolated hot by filtration, to give 740 g of a colourlesspowder which contains 2% of APP.

In similar manner, polymers into which different amounts of APP areincorporated are prepared in accordance with the particulars given inTable 1. The polymers are blended on a two-roll mill for 4 minutes at170° C. with 1% of a lubricant (IRGAWAX® 280, Ciba-Geigy AG), 0.5% of aUV absorber (TINOVIN® P, Ciba-Geigy AG) and 1% of a hindered amine whichis not unsaturated.

The amines used are:

HA-1=bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate

HA-2=bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

The mixtures are compression moulded in a hot press at 180° C. to 2 mmsheets. Test specimens measuring 10×60×2 mm are cut from these sheetsand irradiated with UV light in a Xenotest 450. Samples are taken atregular intervals and assessed for their impact strength according toASTM D 4508-85. The exposed side of the specimen is struck with thependulum. The impact energy required to fracture the specimen isindicated in Table 1. The higher this value, the greater the impactstrength of the specimen. Undamaged specimens exhibit no fracture (NF).

                  TABLE 1                                                         ______________________________________                                                  Concentra-                                                          Concentration                                                                           tion of amine                                                                            Impact strength in kJ/m.sup.2 after                      of grafted                                                                              light sta-                  hours in the                            APP*)     biliser added                                                                            240    320  450  Xenotest 450                            ______________________________________                                        1.5%      0% HA-1    43     35   33                                           1.5%      1% HA-1    NF     61   58                                           0.8%      0% HA-1    47     45   31                                           0.8%      1% HA-1    49     46   34                                           0%        0% HA-1    29     19   18                                           0%        1% HA-1    43     32   29                                           1.5%      1% HA-2    NF     NF   51                                           ______________________________________                                         *)calculated from the N content.                                         

EXAMPLE 2

The copolymer (ABS polymer) is prepared as in Example 1 and, asdescribed therein, blended on a two-roll mill with lubricant, UVabsorber and sterically hindered amine. In addition, 0.5% oftris(nonylphenyl)phosphite (TNPP) is added as processing stabiliser.

The effectiveness of the additives is tested as in Example 1 bydetermining the impact strength after exposure to UV radiation. Theresults are reported in Table 2.

                  TABLE 2                                                         ______________________________________                                        Concen-                                                                              Concen-           Impact strength in kJ/m.sup.2 after                  tration                                                                              tration  Light                   hours in the                          of graf-                                                                             of       stabiliser              Xenotest                              ted APP                                                                              TNPP     added    240  450  950  450                                   ______________________________________                                        1.5%   0%       1% HA-2  NF   51   26                                         1.5%   0.5%     1% HA-2  NF   NF   33                                         ______________________________________                                    

EXAMPLE 3

Example 1 is repeated using polymers containing different amounts ofgrafted APP and of light stabilisers in accordance with the particularsof Table 3.

                  TABLE 3                                                         ______________________________________                                                               Impace strength                                        Concentration                                                                           Concentration                                                                              in kJ/m.sup.2 after                                    of grafted                                                                              of light                 hours in the                               APP       stabiliser added                                                                           500    1550 Xenotest 450                               ______________________________________                                          2.0%    1% HA-1      NF     31                                              0%        2% APP       NF     19                                                        1% HA-1                                                             0%        3% HA-1      NF     25                                              ______________________________________                                         (antioxidant: 0.2% of IRGANOX ® 1076; processing stabiliser: 0.5% of      TNPP)                                                                    

EXAMPLE 4

Example 1 is repeated using polymers containing different amounts ofgrafted APP and of light stabilisers in accordance with the particularsof Table 4.

                  TABLE 4                                                         ______________________________________                                        Concen-  Concentration                                                                             Impact strength in kJ/m.sup.2 after                      tration of                                                                             of light                     hours in the                            grafted APP                                                                            stabiliser added                                                                          250    500  1080 Xenotest 450                            ______________________________________                                          2.0%   0%          NF     NF   23                                             2.0%   1% HA-1     NF     NF   33                                           0%       0%          NF     24   20                                           0%       1% HA-1     NF     NF   13                                           0%       2% APP      NF     NF   14                                                    1% HA-1                                                              ______________________________________                                         (antioxidant: 0.2% of IRGANOX ® 1076; processing stabiliser: 0.5% of      IRGAFOS ® 168)                                                       

EXAMPLE 5

The copolymer is prepared as in Example 1, except that copolymerisationis carried out with 2% of butyl acrylate together with the APP.Compounding is effected as described in Example 1 by incorporating thefollowing additives:

    ______________________________________                                        lubricant       1% of IRGAWAX ® 280                                       UV absorber     0.5% of TINUVIN ® P                                       processing stabiliser                                                                         0.5% of TNPP                                                  amine light stabiliser                                                                        0.5% or 1% of HA-1 or HA-2                                    ______________________________________                                    

The effectiveness of the additives is tested as in Example 1.

The results are reported in Table 5.

                  TABLE 5                                                         ______________________________________                                        Concentration                                                                           Amine light                                                                              Impact strength in kJ/m.sup.2 after                      of grafted                                                                              stabiliser                  hours in the                            APP       added      150    200  380  Xenotest 450                            ______________________________________                                        1.5%      0%         48     30   22                                           1.5%      0.5% HA-1  NF     48   29                                           1.5%      1% HA-1    NF     55   46                                           1.5%      1% HA-2    NF     NF   NF                                           ______________________________________                                    

EXAMPLE 6

The copolymer is prepared as in Example 1, except that4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine (MAPP) is used asHALS. Compounding is effected as in Example 1 by incorporating thefollowing additives:

    ______________________________________                                        lubricant       1% of IRGAWAX ® 280                                       UV absorber     0.5% of TINUVIN ® P                                       processing stabiliser                                                                         0.5% of TNPP                                                  amine light stabiliser                                                                        1% of HA-1 or HA-2                                            ______________________________________                                    

The effectiveness of the additives is tested as in Example 1.

The results are reported in Table 6.

                  TABLE 6                                                         ______________________________________                                        Concentra-                                                                    tion of  Concentra-  Impact strength in kJ/m.sup.2 after                      grafted  tion of light                hours in the                            MAPP     stabiliser added                                                                          250    500  770  Xenotest 450                            ______________________________________                                        2.0%     0%          NF     26   22                                           2.0%     1% HA-1     NF     NF   28                                           2.0%     1% HA-2     NF     NF   27                                           ______________________________________                                    

What is claimed is:
 1. A light-stabilized copolymer of styrene orα-methylstyrene and at least one ethylenically unsaturated comonomer,which copolymer contains crosslinked elastomer particles which aremodified by copolymerization with an unsaturated derivative of asterically hindered amine of formula I or formula II ##STR21## wherein nis 1 or 2 and X is --O-- or --N(R₃)--, R₁ if n=1, is C₁ -C₁₈ alkyl, C₂-C₂₀ alkenyl, C₅ -C₈ cycloalkyl, C₇ -C₉ phenylalkyl, phenyl, phenylwhich is substituted by halogen, C₁ -C₄ alkyl or C₁ -C₄ alkoxy, or is aR₄ OOC--CH═CH-- group and, if n=2, is C₂ -C₁₀ aklylene, vinylene, C₆-C₁₂ arylene or cyclohexylene,R₂ is hydrogen, O., C₁ -C₁₂ alkyl, C₃ -C₅alkenyl, C₇ -C₉ phenylalkyl, C₁ -C₁₈ alkoxy, C₅ -C₈ cycloalkoxy, C₇ -C₉phenylalkoxy, C₂ -C₁₀ alkanoyl, C₃ -C₆ alkenoyl or a group of formula Ia##STR22## R₃ is hydrogen, C₁ -C₁₂ alkyl or C₅ -C₈ cycloalkyl, R₄ ishydrogen or C₁ -C₁₂ alkyl, R₅ is hydrogen, CH₃ or CN, and R₆ ishydrogen, C₁ -C₁₂ alkyl or phenyl,with the proviso that at least one ofthe substituents R₁ and R₂ contains an ethylenic double bond; or##STR23## wherein R₂ is hydrogen, C₁ -C₁₂ alkyl, C₃ -C₅ alkenyl, C₇ -C₉phenylalkyl, C₁ -C₁₈ alkoxy, C₅ -C₈ cycloalkoxy, C₇ -C₉ phenylalkoxy orC₂ -C₁₀ alkanoyl; and which copolymer additionally contains a stericallyhindered amine, which is not unsaturated and which is a derivative of2,2,6,6-tetramethylpiperidine, having formula IV ##STR24## wherein n isan integer from 1 to 4, R₁₁ is H, C₁ -C₄ alkyl, benzyl, acetyl, C₁ -C₁₂alkoxy, C₇ -C₉ phenylalkoxy or cyclohexyloxy, and R₁₂, if n is 1, is theradical of a saturated aliphatic carboxylic acid of 2 to 18 carbonatoms, of a saturated cycloaliphatic carboxylic acid of 7 to 15 carbonatoms, or of an aromatic carboxylic acid of 7 to 15 carbon atoms, and,if n is 2, is the divalent radical of a saturated aliphatic dicarboxylicacid of 2 to 12 carbon atoms, of a saturated cycloaliphatic or aromaticdicarboxylic acid of 8 to 14 carbon atoms, or of a saturated aliphatic,cycloaliphatic or aromatic dicarbamic acid of 8 to 14 carbon atoms, and,if n is 3, is the trivalent radical of a saturated aliphatictricarboxylic acid of 6 to 12 carbon atoms or of an aromatictricarboxylic acid of 9 to 15 carbon atoms, and, if n is 4, is thetetravalent radical of a saturated aliphatic tetracarboxylic acid of 8to 12 carbon atoms or of an aromatic tetracarboxylic acid of 10 to 16carbon atoms.
 2. A stabilised copolymer according to claim 1, which is agraft copolymer of styrene and at least one comonomer on the modifiedelastomer.
 3. A stabilised copolymer according to claim 1, whichcomonomer is acrylonitrile.
 4. A stabilised copolymer according to claim1, which comonomer is methyl methacrylate.
 5. A stabilised copolymeraccording to claim 1, wherein the elastomer particles consist ofpolybutadiene onto which an unsaturated hindered amine is grafted.
 6. Astabilised copolymer according to claim 5, wherein the grafted hinderedamine is a copolymerisable unsaturated derivative of2,2,6,6-tetramethylpiperidine.
 7. A stabilised copolymer according toclaim 6, wherein the grafted hindered amine is4-acryloyloxy-1,2,2,6,6-pentamethylpiperidine.
 8. A stabilised copolymeraccording to claim 1, which contains 0.1 to 10% by weight of thecopolymerised sterically hindered amine and 0.05 to 5% of the stericallyhindered amine which is not unsaturated.
 9. A stabilised copolymeraccording to claim 1, which additionally contains a phenolicantioxidant.
 10. A stabilised copolymer according to claim 1, whichadditionally contains a UV absorber.
 11. A stabilised copolymeraccording to claim 10, which contains a derivative of2-(2-hydroxyphenyl)benzotriazole as UV absorber.
 12. A stabilisedcopolymer according to claim 1, which additionally contains a processingstabiliser of the class of the phosphites or phosphonites.